From Omics Analysis toward Physiological Mechanism Research in Plants.

With the development of big data in system biology researches, the high-throughput omics analysis has become the most popular high technology in the fields of plant research [...].

First Report of Pseudoidium santalacearum Causing Foliar Powdery Mildew on Santalum album in Guangdong Province, China.

Santalum album Linn is an evergreen and facultative root hemiparasitic tree. It is attached to host roots through haustorium to withdraw water and nutrients. Its aromatic heartwood, honored as "Green Gold", is widely used in perfumes, incense, medicine, and skin cancer prevention (Sandeep and Manohara 2019, Polaiah et al. 2020). From February to June 2022, powdery mildew was observed on over 80% of S. album in the nursery with a mean temperature and relative humidity of 30/22°C (day/night) and 55/82% (day/night) at the Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangdong, China (23°11'N, 113°23'E). Initial symptoms were circular to irregular white colonies on the leaf surface (Fig. 1). As the disease progressed, white mycelia covered the entire leaf surface and premature defoliation of the infected leaf was observed. Then a bare stem remained and subsequently desiccated (Sundararaj et al. 2022). Infected leaves with mycelia were collected and observed under a Zeiss AX10 microscope. Foot cells of conidiophores (n = 30) were straight to slightly curved cylindrical, and the length and width of foot cells were up to 24.8 to 44.6 × 8.2 to 11.7 µm. Conidiophores (n = 30) were straight, 83.5 to 127.3 µm long × 6.6 to 7.6 µm wide and produced three immature conidia in chains. Conidia (n = 30) were elliptical to cylindrical, measured 31.3 to 41.2 µm × 11.3 to 13.7 µm. The sexual stage was not found. The morphological characterization of our samples was consistent with powdery mildew of S. album in India, termed Pseudoidium santalacearum (Patel et al. 2015). However, the molecular identification was not performed. In this study, we carefully collected the mildew and extracted the genomic DNA. The internal transcribed spacer (ITS) region of rDNA was amplified using universal primers ITS1 and ITS4 (White et al. 1990). The ITS sequences of the three samples (GenBank Accession No. OQ746371, OQ746372, and OQ746373) were all more than 99% identical with the sequence of Erysiphe palczewskii on Caragana arborescens (GenBank Accession No. LC010048) (Takamatsu et al. 2015). It is known that Erysiphe containing chasmothecia belongs to teleomorph, whereas Pseudoidium is an asexual morph of Erysiphe, belonging to anamorph (Hsiao et al. 2022, Meeboon and Takamatsu 2016). In our samples, there was no chasmothecia, and the morphological characterization was consistent with P. santalacearum (Patel et al. 2015). Therefore, we classified it as P. santalacearum. Phylogenetic analysis showed that P. santalacearum had a closer relationship with the E. palczewskii (Fig. 2). Pathogenicity tests were conducted by gently pressing the infected leaves onto five healthy S. album plants. Five non-inoculated plants were used as controls. The plants were placed in a growth chamber (Light/Dark: 16 h/8 h, temperature: 25 ± 2°C). Inoculated leaves developed powdery mildew symptoms after 7-12 days, whereas the control plants remained symptomless (Fig. 1). Morphological and molecular characters of the fungus on the inoculated plants were identical to those on naturally infected S. album, fulfilling Koch's postulates. To our knowledge, this is the first report of P. santalacearum on S. album in Guangdong, China. Powdery mildew can generally result in a high mortality of S. album seedlings. Therefore, identification of the pathogen provides a scientific basis for effective diagnosis and prevention of the disease and contribute to an appropriate nursery management of S. album seedlings.

PRMT2 promotes RCC tumorigenesis and metastasis via enhancing WNT5A transcriptional expression.

Protein arginine methyltransferase 2 (PRMT2) is involved in several biological processes via histone methylation and transcriptional regulation. Although PRMT2 has been reported to affect breast cancer and glioblastoma progression, its role in renal cell cancer (RCC) remains unclear. Here, we found that PRMT2 was upregulated in primary RCC and RCC cell lines. We demonstrated that PRMT2 overexpression promoted RCC cell proliferation and motility both in vitro and in vivo. Moreover, we revealed that PRMT2-mediated H3R8 asymmetric dimethylation (H3R8me2a) was enriched in the WNT5A promoter region and enhanced WNT5A transcriptional expression, leading to activation of Wnt signaling and malignant progression of RCC. Finally, we confirmed that high PRMT2 and WNT5A expression was strongly correlated with poor clinicopathological characteristics and poor overall survival in RCC patient tissues. Our findings indicate that PRMT2 and WNT5A may be promising predictive diagnostic biomarkers for RCC metastasis. Our study also suggests that PRMT2 is a novel therapeutic target in patients with RCC.

Nitrogen rather than carbon released by litter decomposition mediates nutrient relationships in a multispecies forest plantation with hemiparasite.

Hemiparasitic plants influence community composition by altering nutrient cycling. Although hemiparasites can deplete a host's nutrients via parasitism, their potentially positive effects on nutrient return to multispecies communities remain unclear. We used 13C/15N-enriched leaf litter of the hemiparasite sandalwood (Santalum album, Sa) and two N2-fixing hosts of acacia (Acacia confusa, Ac) and rosewood (Dalbergia odorifera, Do), either as a single-species or mixed-species litter, to elucidate nutrient return by litter decomposition in an acacia-rosewood-sandalwood mixed plantation. We determined litter decomposition rates, litter C and N release, and the resorption of C and N from seven litter types (Ac, Do, Sa, AcDo, AcSa, DoSa, and AcDoSa) at 90, 180, 270, and 360 days. We found that non-additive mixing effects were common during the decomposition of mixed litter and depended on litter type and decomposition timing. After rapidly increasing for around 180 days, both the decomposition rate and release of C and N from litter decomposition declined, but the resorption of litter-released N by the target tree species increased. There was a 90-day lag time between the release and resorption of litter N. Sandalwood litter consistently stimulated the litter mass loss of its mixed litter. Rosewood had the highest release rate of litter 13C or 15N from litter decomposition, but resorbed more litter 15N into its leaves than other tree species. In contrast, acacia had a lower decomposition rate and a higher 15N resorption in its roots. Initial litter quality was closely correlated with the release of litter 15N. Neither the release nor resorption of litter 13C significantly differed among sandalwood, rosewood, and acacia. Our study demonstrates that the fate of litter N, rather than litter C, mediates nutrient relationships in mixed sandalwood plantations and thus provides important silvicultural implications for planting sandalwood with other host species.

Hierarchical network relaxation of a dynamic cross-linked polyolefin elastomer for advanced reversible shape memory effect.

Reversible shape-memory polymers (RSMPs) are highly desired for soft actuators due to the repeatability of deformation. Herein, a polyolefin elastomer vitrimer (POEV) was prepared by constructing a dynamic cross-linked network based on boronic ester bonds. POEV showed varied network relaxation in a wide temperature range due to hierarchical network relaxation, and then the entropy decreased and the relaxation of POEV chains was facilely controlled by temperature. The controllable relaxation of POEV by programming the temperature enabled the actuation domain with a reduction in entropy and the skeleton domain with a relatively high entropy can be built in POEV, greatly affecting the reversible shape memory effects (RSMEs). The topological rearrangement resulted from the activated exchange of dynamic covalent bonds, which enables POEV with good shape reconfigurability, and allows for complicated 3D shapes and shape-shifting on demand. More interestingly, combining the decreasing entropy of POEV chains and fully topological rearrangement tailored by temperature, hybrid aligned carbon nanotubes (CNTs) can be constructed in POEV via a two-stage training. Then, the aligned CNTs can enhance the elasticity and act as a hybrid skeleton for RSMEs, avoiding the negative impact of CNTs on the reversible actuation strain. The hierarchical network relaxation facilitates combining all these unusual properties in one shape memory network synergistically, paving new avenues for realizing smart materials with advanced RSME.

Host root exudates initiate a foraging preference by the root parasite Santalum album.

Haustoria of root-parasitic plants draw nutrients from the roots of host species. While recent studies have assessed host preferences of parasitic plants, how root-exuded chemicals can mediate host tropism and selection by root-parasitic plants is poorly understood. Under greenhouse conditions, we performed two pot experiments to determine whether the root parasite Santalum album selectively forages for superior hosts (N2-fixing Acacia confusa Merr. or Dalbergia odorifera T. Chen) rather than for inferior hosts (non-N2-fixing Bischofia polycarpa (levl.) Airy Shaw or Dracontomelon duperreranum Pierre), and whether S. album uses host root exudates and/or specific chemicals in these root exudates to locate and trigger haustorium formation. Lateral roots and haustoria of S. album seedlings exhibited greater growth in the direction of D. odorifera roots than toward roots from the other three hosts. Comparative metabolic analysis revealed that D. odorifera root exudates were enriched in isoflavonoid, flavonoid and flavone/flavonol biosynthesis pathways, and that the relative contents of flavonoids were significantly greater in the root exudates of D. odorifera than in those of the other three hosts. Root exudates from D. odorifera significantly promoted S. album root growth, haustorium formation and reactive oxygen species accumulation in haustoria. Our results demonstrate that the key step in plant parasitism by S. album is based on root exudation by a host plant; the exudates function as a metabolite signal that activate lateral root growth and haustorium formation. Our results also indicate that flavonoids in the root exudates could play an important role in S. album foraging activity. Information on the responses of root parasites to host root exudates and/or haustorium-inducing chemicals may be useful for selecting superior host species to plant with valuable species of root parasites.

Analysis of Rac/Rop Small GTPase Family Expression in Santalum album L. and Their Potential Roles in Drought Stress and Hormone Treatments.

Plant-specific Rac/Rop small GTPases, also known as Rop, belong to the Rho subfamily. Rac proteins can be divided into two types according to their C-terminal motifs: Type I Rac proteins have a typical CaaL motif at the C-terminal, whereas type II Rac proteins lack this motif but retain a cysteine-containing element for membrane anchoring. The Rac gene family participates in diverse signal transduction events, cytoskeleton morphogenesis, reactive oxygen species (ROS) production and hormone responses in plants as molecular switches. S. album is a popular semiparasitic plant that absorbs nutrients from the host plant through the haustoria to meet its own growth and development needs. Because the whole plant has a high use value, due to the high production value of its perfume oils, it is known as the "tree of gold". Based on the full-length transcriptome data of S. album, nine Rac gene members were named SaRac1-9, and we analyzed their physicochemical properties. Evolutionary analysis showed that SaRac1-7, AtRac1-6, AtRac9 and AtRac11 and OsRac5, OsRacB and OsRacD belong to the typical plant type I Rac/Rop protein, while SaRac8-9, AtRac7, AtRac8, AtRac10 and OsRac1-4 belong to the type II Rac/ROP protein. Tissue-specific expression analysis showed that nine genes were expressed in roots, stems, leaves and haustoria, and SaRac7/8/9 expression in stems, haustoria and roots was significantly higher than that in leaves. The expression levels of SaRac1, SaRac4 and SaRac6 in stems were very low, and the expression levels of SaRac2 and SaRac5 in roots and SaRac2/3/7 in haustoria were very high, which indicated that these genes were closely related to the formation of S. album haustoria. To further analyze the function of SaRac, nine Rac genes in sandalwood were subjected to drought stress and hormone treatments. These results establish a preliminary foundation for the regulation of growth and development in S. album by SaRac.

Vincosamide Has a Function for Inhibiting Malignant Behaviors of Hepatocellular Carcinoma Cells.

Background: Vincosamide (Vinco) was first identified in the methanolic extract of the leaves of Psychotria leiocarpa, and Vinco has important anti-inflammatory effects and activity against cholinesterase, Vinco also has a trait to anti-tumor. However, whether Vinco can inhibit the malignant behaviors of hepatocellular carcinoma (HCC) cells is still unclear. In the present study, we explored the role of Vinco in suppressing the malignant behaviors of HCC cells. Methods: MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-tetrazolium bromide), trypan blue exclusion assay, the Cell Counting Kit (CCK)-8 and flow cytometric analysis were applied to detect the proliferation and apoptosis of HCC cells; electron microscopy was performed to observe the change of cellular mitochondrial morphology; scratch repair and Transwell assays were used to analyze the migration and invasion of HCC cells; expression and localization of proteins were detected by laser confocal microscopy and Western blotting; the growth of the cancer cells in vivo was assessed in a mouse tumorous model. Results: At a dose of 10 - 80 µg/mL, Vinco inhibited the proliferation, migration, invasion and promoted apoptosis of HCC cells in a dose-dependent manner but had low cytotoxicity effect on normal liver cells. Additionally, 80 µg/mL of Vinco could significantly disrupt the morphology of mitochondria, suppress the migration and invasion of HCC cells. The growth of HCC cells in the animal tumorous model was significantly inhibited after treatment with Vinco (10 mg/kg/day) for 3 days. The results of the present study indicated that Vinco (10 - 80 µg/mL) played a role in activating caspase-3, promoting the expression of phosphate and tension homology deleted on chromosome 10 (PTEN), and inhibiting the phosphorylation of AKT (Ser473) and mTOR (Thr2448); Vinco also has a trait for suppressing the expression of CXCR4, Src, MMP9, EpCAM, Ras, Oct4 and cancer stem cell "stemness markers" CD133 and CD44 in HCC cells. Conclusions: Vinco has a role in inhibiting the malignant behaviors of HCC cells; the role molecular mechanism of Vinco may be involved in restraining expression of the growth-, metastasis-related factors, such as Src, Ras, MMP9, EpCAM, CXCR4; activating the activity of caspase-3 and blocking PI3K/AKT signaling pathway. Thus, Vinco should be considered as a new chemotherapy agent for HCC patients.

A Wave-Driven Piezoelectrical Film for Interfacial Steam Generation: Beyond the Limitation of Hydrogel.

Solar interfacial vapor generation based on low evaporation energy requirements is an effective technology to speed up water purification under natural sunlight, offering great potential to alleviate the current global water crisis. The external electric field and hydrogel are two independent methods enabling low-energy water evaporation. However, the complicated external equipment for generating an electric field and the restricted activation area of hydrogels significantly limit their practical application in steam generation. Thus, a piezoelectric fiber membrane is embedded into a highly hydratable light-absorbing poly(vinyl alcohol) (PVA) hydrogel for synergistic water activation. The integrated evaporator is capable of continuously converting the wave energy reserved in the ocean into electrical energy, activating the water in the hydrogel. It is found that the activation effect leads to an improvement of over 23% compared to a non-piezoelectric hydrogel evaporator. This work provides an evaporation prototype based on the synergistic water activation of wave-triggered electricity and highly hydratable hydrogel.

LncRNA LINC00460 facilitates the proliferation and metastasis of renal cell carcinoma via PI3K/AKT signaling pathway.

Renal cell carcinoma (RCC) is one of the most prevalent cancers diseases in the worldwide. Long noncoding RNAs (LncRNAs) have been indicated as a mediator acted in tumorigenesis of RCC. LINC00460 has been reported to participate in many kinds of malignancies and promotes cancer progressions. However, the mechanism of LINC00460 on RCC is yet to be investigated. This study aimed to explore the potential function and regulation mechanism of LINC00460 in RCC. We analysed the LINC00460 expression and the prognosis in RCC patients using Gene Expression Profiling Interactive Analysis (GEPIA) and The Cancer Genome Atlas (TCGA) databases. LINC00460 level in normal renal cell line and RCC cell lines were examined by qRT-PCR. We study the effects of LINC00460 on proliferation, migration, invasion, apoptosis in RCC cells lines using a series of in vivo and in vitro experiments. RNA sequencing (RNA-seq) analysis was applied to searching potential LINC00460 related signal pathway in RCC. We identified the significant up-regulated expression of LINC00460 both in RCC tissues and cell. RCC patients with elevated LINC00460 expression have shorter survival. Up-expression of LINC00460 promoted cell proliferation, invasion and migration, meanwhile down-regulation of LINC00460 exerted inhibitory effect on these activities. We crucially identified that LNC00460 promotes development of RCC by influencing the PI3K/AKT pathway. Knockdown of LNC00460 decreased the phosphorylation of AKT and mTOR. The key finding of our study showed that LINC00460 functions as an oncogene in RCC pathogenesis by mediating the PI3K/AKT.

First Report of Phytoplasma Belongs to 16SrV Group Associated with Witches'-broom Disease of Taxillus chinensis in China.

Taxillus chinensis (DC.) Danser is a hemiparasitic shrub, widespread in Southern China (Fu et al., 2001). T. chinensis can parasitize a wide range of species (e.g., Camellia spp., Ficus virens and Osmanthus fragrans), which obviously suppressed host growth by robbing nutrient and water through haustorium, causing considerable tree damage. During field visits to Dongguan (22°86'N, 13°97'E) and Guangzhou (23°19'N, 113°31'E), Guangdong Province, in April-July 2021, the typical phytoplasma-suspected symptom manifested as stunting, leaflet, leaf chlorosis and witches'-broom were observed in almost 36% of T. chinensis plants. Leaf samples were collected from six randomly collected plants with symptoms and six symptomless plants (Fig 1). Among them, half of T. chinensis plants parasitized on the host Elaeocarpus sylvestris, the other half on the O. fragrans. No apparent symptoms were observed on both two host plants. Total DNA was extracted from 0.5 g fresh leaf of T. chinensis plants with and without symptoms, as well as two host plants E. sylvestris and O. fragrans, using the CTAB method (Doyle et al., 1990). Nested polymerase chain reactions (PCRs) were performed on DNA extracts of all tested plants with primer pairs of P1/P7 and R16mF2/R16mR1 for 16S rRNA gene (Lee et al., 1993) and rp(v)F1/rpR1 for rp gene (Lee et al., 1998). All amplicons were obtained from symptomatic samples of T. chinensis and host plant E. sylvestris, whereas no such products resulted from DNAs of symptomless plants and O. fragrans. The amplicons were purified and sequenced by Sanger method (Rui Biotech, Guangzhou, China). The amplicon of 16S rRNA and rp genes is 1346 bp and 938 bp, respectively. BLAST comparison of the 16S rRNA (accession no. OL412744) and rp (accession no. OL473789) sequences of the T. chinensis witches'-broom phytoplasma yielded 99.6% sequence identity with those of phytoplasmas of group 16SrV jujube witches'-broom (JWB) phytoplasma (accession no. CP025121 for 16S rRNA gene and AF396941 for rp gene). The 16S rRNA gene sequence of phytoplasma in host plant E. sylvestris (accession no. OM885990) is 99.7% similarity to the 'Elaeocarpus zollingeri' yellows phytoplasma (accession no. LC257960) and 99.4% similarity to the 'Elaeocarpus sylvestris' decline phytoplasma (accession no. MW553140), but 95.8% similarity to the 16S rRNA gene of phytoplasma in T. chinensis. The virtual RFLP tool, iPhyClassifier delineated the T. chinensis phytoplasma (accession no. OL412744) to group 16SrV-B (accession no. AB052876) with the similarity coefficient 1.0 (Fig 2), and phytoplasma in E. sylvestris to group 16Sr group XXXII with the similarity coefficient 0.97. Phylogeny analyses of 16S rRNA and rp genes (MEGA version 7.0.14, USA) using reference phytoplasmas from GenBank confirmed sequencing results and placed the T. chinensis phytoplasma in group 16SrV-B (Fig. 3 and 4). In China, the 16SrV-B phytoplasma group has been reported in Amaranthus retroflexus (Yang et al., 2011), Liriodendron chinense (Li et al., 2012), Prunus salicina (Gao et al., 2020) and sweet potato (Li et al., 2021). This is the first report of a 'Ca. Phytoplasma ziziphi', 16SrV-B related phytoplasma associated with parasitic T. chinensis in China. The results of this study indicate that T. chinensis could be a vector to spread phytoplasmas 16SrV group through parasitism and this can be helpful for related research.

TRIM21 deficiency promotes cell proliferation and tumorigenesis via regulating p21 expression in ovarian cancer.

Tripartite motif-containing 21 (TRIM21) has been reported to have a cancer-promoting or anticancer effect in various tumors; however, its role in ovarian cancer (OC) remains to be elucidated. In this study, we explored the biological function of TRIM21 in OC progression and investigated the potential mechanisms. We found that TRIM21 was remarkably decreased in OC tissues and cell lines compared with adjacent-cancerous tissues and normal ovarian epithelium cell. Decreased expression of TRIM21 in OC patients was significantly correlated with shorter overall and disease-specific survival by The Cancer Genome Atlas database (TCGA) analysis. Functional assays revealed that TRIM21 inhibited the migration and invasion of OC cells; and that TRIM21 also obviously impaired cell proliferation by inhibiting cell cycle progression in vitro and in vivo. Taken together, our results suggest that TRIM21 may be a promising biomarker and target for OC diagnosis and treatment.

The yellowhorn AGL transcription factor gene XsAGL22 contributes to ABA biosynthesis and drought tolerance in poplar.

Regulation of abscisic acid (ABA) biosynthesis helps plants adapt to drought stress, but the underlying molecular mechanisms are largely unclear. Here, a drought-induced transcription factor XsAGL22 was isolated from yellowhorn (Xanthoceras sorbifolium Bunge). Yeast one-hybrid and electrophoretic mobility shift assays indicated that XsAGL22 can physically bind to the promoters of the ABA biosynthesis-related genes XsNCED6 and XsBG1, and a dual-luciferase assay showed that XsAGL22 activates the promoters of the later two genes. Transient overexpression of XsAGL22 in yellowhorn leaves also increased the expression of XsNCED6 and XsBG1 and increased cellular ABA levels. Finally, heterologous overexpression of XsAGL22 in poplar increased ABA content, reduced stomatal aperture and increased drought resistance. Our results suggest that XsAGL22 is a powerful regulator of ABA biosynthesis and plays a critical role in drought resistance in plants.

Interfacial Radiation-Absorbing Hydrogel Film for Efficient Thermal Utilization on Solar Evaporator Surfaces.

Solar water purification is a promising technology with a strong potential for producing fresh water without effluent discharge. For energy-intensive interfacial vapor generation, energy loss to air via heat radiation and convection occurs commonly but is normally ignored, which severely limits the energy efficiency. Therefore, it is necessary to precisely regulate the interfacial thermal energy for interfacial vapor generation. Here, we developed a hierarchically porous radiation-absorbing hydrogel film (hp-RAH) through an in situ gelation strategy and employed this hp-RAH on various existing solar evaporator surfaces. The hydrogel film efficiently absorbs and reutilizes the thermal radiation energy emitted by the photothermal layer and eradicates thermal convection of the photothermal layer into air. In this way, an evaporation efficiency up to 95% is obtained, and the heat radiation and convection losses are reduced from 6.6% to 0.39% under 1 sun. This strategy demonstrates a promising membrane evaporation prototype based on the evaporation surface thermal utilization.

Effects of arbuscular mycorrhizal inoculation on the growth, photosynthesis and antioxidant enzymatic activity of Euonymus maackii Rupr. under gradient water deficit levels.

The role of arbuscular mycorrhizal (AM) fungus (Rhizophagus intraradices) in the amelioration of the water deficit-mediated negative influence on the growth, photosynthesis, and antioxidant system in Euonymus maackii Rupr. was examined. E. maackii seedlings were subjected to 5 water deficit levels, soil water contents of 20%, 40%, 60%, 80% and 100% field capacity (FC), and 2 inoculation treatments, with and without AM inoculation. The water deficit increasingly limited the seedling height, biomass accumulation in shoots and roots, chlorophyll content, gas exchange and chlorophyll fluorescence parameters with an increasing water deficit level. In addition, water deficit stimulated the activities of antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), in both shoots and roots, except under 20% FC conditions. E. maackii seedlings under all water deficit conditions formed symbiosis well with AM fungi, which significantly ameliorated the drought-mediated negative effect, especially under 40% and 60% FC conditions. Under 40% to 80% FC conditions, AM formation improved seedling growth and photosynthesis by significantly enhancing the biomass accumulation, chlorophyll content and assimilation. Mycorrhizal seedlings showed better tolerance and less sensitivity to a water deficit, reflected in the lower SOD activities of shoots and roots and CAT activity of shoots under 40% and 60% FC conditions. Downregulation of the antioxidant system in mycorrhizal seedlings suggested better maintenance of redox homeostasis and protection of metabolism, including biomass accumulation and assimilation. All the results advocated the positive role of R. intraradices inoculation in E. maackii against a water deficit, especially under 40% FC, which suggested the distinct AM performance in drought tolerance and the potential role of the combination of E. maackii-AM fungi in ecological restoration in arid regions.

Soil properties and microbial community in the rhizosphere of Populus alba var. pyramidalis along a chronosequence.

By maintaining soil structure and quality, soil microbial communities usually play important role in many forest ecosystem processes, including ecological succession. Understanding changes in the microbial communities of areas afforested with stands of different ages is of interest in ecology. Populus alba var. pyramidalis Bunge has been widely planted in Northwest China for ecological restoration. Rhizospheric soil samples were collected from 4-, 9-, 15-, 25- and 30-year-old plantations of P. alba to measure soil characteristics and soil microbial community diversity using Illumina MiSeq sequencing. The soil nutrition concentration and enzymatic activities decreased with depth of soil layer increased. In terms of stand age, alkaline phosphatase and dehydrogenase and the contents of nitrate N, available P and soil organic content (SOC) increased gradually. According to Illumina MiSeq sequencing results, the fungal and bacterial community structure varied with stand age, and diversity of fungi was less than bacteria. With increasing stand age, fungal community diversity indexes first increased and then decreased, peaked at 25y or 30y. RDA results suggested that soil available P and nitrate N were the most important factors governing fungal community structure, while available P contributed significantly to the variance of the bacterial community. Structural equation modelling (SEM) results indicated soil available P, nitrate N and SOC contents largely explained the shift in the microbial community structure along the cultivation chronosequence, and soil enzyme activities were related with changes in microbial community. Our results illustrated that the successional changes in microbial communities in the P. alba plantations can largely be attributed to changes in soil nutrition level along the chronosequence.

Long noncoding RNA SH3PXD2A-AS1 promotes colorectal cancer progression by regulating p53-mediated gene transcription.

Long non-coding RNAs (lncRNAs) play key roles in various human cancers. We aimed to determine the key lncRNAs mediating colorectal cancer (CRC) progression. We identified some lncRNAs aberrantly expressed in CRC tissues by using lncRNA microarrays and demonstrated that SH3PXD2A-AS1 was one of the most highly overexpressed lncRNAs in CRC. We further aimed to explore the roles and possible molecular mechanisms of SH3PXD2A-AS1 in CRC. RNA ISH revealed that SH3PXD2A-AS1 was overexpressed in CRC compared with adjacent normal colon tissues and indicated poor prognosis in CRC. Functional analyses showed that SH3PXD2A-AS1 enhanced cell proliferation, angiogenesis, and metastasis. Mechanistically, SH3PXD2A-AS1 can directly interact with p53 protein and regulate p53-mediated gene transcription in CRC. We provided mechanistic insights into the regulation of SH3PXD2A-AS1 on p53-mediated gene transcription and suggested its potential as a new prognostic biomarker and target for the clinical management of CRC.

Analysis of Populus glycosyl hydrolase family I members and their potential role in the ABA treatment and drought stress response.

Glycoside hydrolase family 1 (GH1) ß-glucosidases (BGLUs) are encoded by a large number of genes and are involved in many developmental processes and stress responses in plants. Due to their importance in plant growth and development, genome-wide analyses have been conducted in the model plant species Arabidopsis thaliana, rice and maize but not in woody plant species, which have important economic and ecological value. In this study, we systematically analyzed Populus BGLUs (PtBGLUs) and demonstrated the involvement of several genes under stress conditions. Forty-four PtBGLUs were identified in Populus databases; these genes were located on 11 chromosomes, and the proteins of several PtBGLU genes were highly similar. More than 90% of PtBGLUs contain three conserved motifs. Collinearity results showed that 44 PtBGLU genes resulted from 12 tandem and 5 segmental duplication events. Phylogenetic analysis revealed that 128 BGLU genes from Populus trichocarpa, A. thaliana and Oryza sativa could be classified into 4 subgroups and subgroup Ⅱ and Ⅳ were differently having PtBGLUs and AtBGLUs. We further investigated whether several PtBGLUs responded to drought stress and ABA treatment, and the results showed that most of the selected BGLU genes were expressed in response to stress, which is consistent with previous studies involving rice and Arabidopsis homologous genes. Large numbers of stress-, hormone-, and development-related elements in the PtBGLU promoters suggest that BGLU genes may be involved in complex networks. Taken together, our results provide valuable information for an improved understanding of ß-glucosidase function in woody plants.

LncRNA-NONHSAT024778 promote the proliferation and invasion of chordoma cell by regulating miR-1290/Robo1 axis.

Chordoma is a malignant bone tumor originating from the embryonic remnants of the notochord. lncRNAs act as competing endogenous RNAs (ceRNAs) and play a critical role in tumor pathology. However, the biological role of lncRNA-NONHSAT024778 and the underlying molecular mechanism in chordoma remains unknown. qRT-PCR was used to analyze the expression changes of NONHSAT024778 and miR-1290 in chordoma tissues and cell lines. Bioinformatics analysis and luciferase reporter assay were applied to detect the targeting binding effect between NONHSAT024778 and miR-1290, and between Robo1 and miR-1290. The effect of NONHSAT024778 on chordoma cell proliferation and invasion and its regulation of miR-1290 by acting as a ceRNA were also investigated. An increased NONHSAT024778 expression was correlated with a decreased miR-1290 level in chordoma tissues. NONHSAT024778 knockdown suppressed the proliferation and invasion of chordoma cells. miR-1290 restored expression rescued the carcinogenic function of NONHSAT024778. Bioinformatics analysis showed that NONHSAT024778 acted as ceRNA to regulate Robo1 via sponging miR-1290 in chordoma cells, thereby promoting chordoma cell malignant progression. In vivo results confirmed the anti-tumor effects of NONHSAT024778 knockdown activating miR-1290 to inhibit the oncogene Robo1. NONHSAT024778 is substantially overexpressed, whereas miR-1290 is decreased in chordoma tissue. NONHSAT024778-miR-1290-Robo1 axis plays a critical role in chordoma tumorigenesis and might be a potential predictive biomarker for the diagnosis and therapeutic target among patients with chordoma.